Textile heating and cooling

ABSTRACT

In order to accomplish rapid cooling of synthetic thermoplastic continuous filament yarn which has been heated for bulking or the like, the yarn is led along a groove and subjected to jets of cooling gas spaced along the groove. For bulking in the preferred form the yarn is false twisted and heated suitably by a rotating drum heater having a smooth descending conical portion toward a take off end, and a downward step at one end of the smooth conical portion. In another form, the drum heater has two right cylindrical portions of different diameter, the smaller being at the outlet end, and a step separating them. In another form two ends of yarn are applied, and then the yarn is continuously brought into or against a heater, preferably a rotating drum heater.

llnited States Patent McCard [54] TEXTILE HEATING AND COOLING lnventor:Henry W. McCard, 208 Rodman Avenue, Jenkintown, Pa. 19046 Notice: Theportion of the term of this patent subsequent to July 7, 1987,

has been disclaimed.

Filed: Nov. 7, 1969 Appl. No.: 874,764

Related US. Application Data Continuation-impart of Ser. No. 751,785,Aug. 12, 1968, Pat. No. 3,518,822.

References Cited- UNITED STATES PATENTS 4/1943 Brockel ..34/155 X 5/1950 Sisson ..34/23 X 11/1953 Merriman ..34/23 X 7/ 1960 Van Dijk..57/34 HS 51 *Oct. 10, 1972 Primary Examiner-John PetrakesAttorney-Jackson, Jackson & Chovanes [57] ABSTRACT In order toaccomplish rapid cooling of synthetic thermoplastic continuous filamentyarn which has been heated for bulking or the like, the yarn is ledalong a groove and subjected to jets of cooling gas spaced along thegroove. For bulking in the preferred form the yarn is false twisted andheated suitably by a rotating drum heater having a smooth descendingconical portion toward a take off end, and a downward step at one end ofthe smooth conical portion. In another form, the drum heater has tworight cylindrical portions of different diameter, the smaller being atthe outlet end, and a step separating them. In another form two ends ofyarn are applied, and then the yarn is continuously brought into oragainst a heater, preferably a rotating drum heater.

9 Claims, 8 Drawing Figures PATENTEDnm 10 612 SHEET 2 [IF 3 INVENTOR.Henry W MC Cam! PATENTEDucf i 0 an 3.696; 601

SHEET 3 or 3 I INVENTO #422)? ik/f/c 6'42 BY W ATTORNEYS TEXTILE HEATINGAND COOLING The present application is a continuation-in-part of mycopending application Ser. No. 751,785, filed Aug. 12, 1968, for TextileHeater and Process, now U.S. Pat. 3,518,822.

DESCRIPTION OF INVENTION The present invention relates to textilemachinery for producing bulked synthetic thermoplastic continuousfilament yarn and to processes therefor.

A purpose of the invention is to improve the rapid cooling of syntheticthermoplastic continuous filament yarn which has been heated in order topermit it to shrink and bulk and particularly to render cooling possibleat higher speeds of yarn progression.

A further purpose is to false twist yarn, to heat the false twistedyarn, preferably by a rotating drum heater to be described, and to coolthe yarn by cooling gas jets against its side along a groove.

A further purpose is to ply two ends of synthetic thermoplasticcontinuous filament yarn twisted with respect to one another, to bringthe plied yarn against the outside of a rotatable drum heater so as toheat the yarn and to drop the yarn over a step at one end or the otherof the smooth conical portion, and then cool the yarn by progressing itin airborn fashion along a groove where it is subjected to a series oftransverse cooling gas jets, and finally to separate the yarn ends.

A further purpose is to heat the yarn to be false twisted by a drumhaving a large inlet right cylindrical portion and a small outlet rightcylindrical portion separated by a step, the small portion preferablyhaving groove walls separating yarn paths.

Further purposes appear in the specification and in the claims. FIG. 1is a diagram showing the complete textile operation of plying two yarnends twisted together, heating on a drum heater, rapidly cooling to setthe bulk effect and then deplying or separating the yarn ends andforming packages.

FIG. 2 is a diagram showing bulking of yarn by false twisting accordingto the preferred form of the invention.

FIG. 3 is a fragmentary axial section of a preferred drum heateraccording to the invention.

FIG. 4 is a perspective of the cooling mechanism illustrated, with aportion broken away to show the construction at the cooling groove.

FIG. 5 is a section of one form of cooling mechanism on the line 4-4 ofFIG. 3.

FIG. 6 is a diagrammatic cross-sectional illustration of the yarntraveling along the groove.

FIG. 7 is a fragmentary side elevation of the cooling I device showing apreferred orientation of the orifices.

FIG. 8 is a side elevation a further variant form of heater drum of theinvention.

In the prior art numerous processes have been developed for creatingbulk and yarn stretch characteristics in synthetic thermoplasticcontinuous filament yarn such as nylon and the like. The problem isrendered difficult by operation at higher and higher linear speeds,speeds of 40 yards per minute now being employed, and spindle speedssometimes running as high as 150,000 rpm.

Usually the creation of bulk and stretch characteristics involves acombination of heating and twisting and then cooling so that the effectof the twist is set.

While strip heaters have been used, there is a considerable advantage inemploying rotatable drum heaters, for example, according to McCard andRoss U.S. Pat. No. 3,420,983, granted Jan. 7, 1969, for Rotating DrumHeater for Synthetic Yarn.

In a preferred embodiment of the invention, synthetic thermoplasticcontinuous filament yarn is run through a false twister. While the yarnis subjected to false twist it is heated preferably by a drum heater tobe described, or by a strip or other heater. While the heated yarn isstill subjected to twist and heat, it is suddenly cooled by runningalong a groove past cooling gas jets.

When false twist is applied to yarn heated on some drum heaters, theyarn undergoes shrinkage as a result of the heating and cooling, andthere is a pronounced tendency, even if the heater allows for theshrinkage, for the yarn ends to break at or adjacent to the drum heater.In my U.S. Pat. Application Ser. No. 751,785, above referred to,provision has been made to correct this difficulty. The breakage is dueto the tendency of false twist to back up toward the place from whichthe yarn is coming.

By bringing untwisted yarn on to the heater drum on a smooth cylindricalpre-heating section and then passing the yarn along a smooth conicalportion having an abrupt step at one. or the other end thereof,allowance is made for backing up of the twist from the spindle to and onto the heater drum. Yarn ends tend to adjust their position along theaxis of the drum to compensate for the backup of the twist.

In another form of drum configuration, which I have found to besatisfactory for processing false twist yarn, the yarn is brought on tothe smooth cylindrical preheating section of the drum and is led overthe separator pin and then on to the drum repeatedly, until a sufficientnumber of passes have been made so the contact time at temperature issufficient to raise the yarn to its plastic temperature range. The yarnis then led into the grooves (all of the same diameter, approximately)which permits the twist to back up on to the heated drum and to beheated and heat-set in the twisted state.

One of the difficulties still remaining is that it is important toaccomplish the cooling very quickly, notwithstanding the rapid forwardprogression of the yarn which has been heated. If the cooling isaccomplished by direct surface contact, there is danger of creatingstress in the yarn in contact with the cooling surface, and abrading theyarn against such surface. One of the important features of the presentinvention is to support the yarn in an airborne condition as it issubjected to cooling gas, preferably air. Reliance is had on Bemoullisprinciple to keep the yarn airborne as it is subjected to a sequence oftransverse gas jets.

One way of false twisting the yarn of the invention is by the duo-twistprocess which is used for creating bulk and stretch by twisting two yarnends together to produce plied yarn to render it thermoplastic and thencooling to set the yarn, the bulked yarn ends being subsequentlyseparated and formed into packages. See Carothers U.S. Pat. No.3,091,908, granted June 4, 1963.

It is believed that the best application of the invention is likely tobe in creating nylon yarn with bulked and stretch characteristics fromnylon continuous fila ment yarn usually having multifilaments. For thispurpose, the outside temperature of the heating drum should beapproximately 400 F., that is, in the range between 350 and 450 F.,which will render the nylon thermoplastic.

The invention is also applicable to other continuous filament syntheticthermoplastic yarns at appropriate temperatures for heating each ofthem, for example polyester, polyvinylchloride, polyvinylchlorideacetate and polypropylene yarns.

The invention is intended to be applied to continuous filament syntheticthermoplastic yarn, examples being 70 denier, 34 filament nylon yarn,and 17 denier, l7 filament nylon yarn.

The broad concept of running yarn over a cone with takeoff at the smallend is old in Cadden U.S. Pat. No. 2,218,504, granted Oct. 22, 1940, andStanley U.S. Pat. No. 3,221,385, granted Dec. 7, 1965. Running yarn overa cone with takeoff at the large end is shown by Cotchett U.S. Pat. No.2,174,688, granted Oct. 3, 1939, and McCrosky U.S. Pat. No. 2,370,180,granted Feb. 27, 1945. None of these devices provides a cylindrical drumheater having a smooth cone descending from the cylinder to a takeoff atthe small end with an abrupt step at one or the other end of the smoothconical portion.

FIG. 1 illustrates diagrammatically equipment to which the invention isapplicable, and a process for creating bulked thermoplastic continuousfilament yarn. This Figure shows a duo-twist installation for creatingbulked and stretch characteristics in continuous filament thermoplasticyarn, such as nylon.

A yarn end 20 is withdrawn from a source of yarn 21 and passes throughthe hollow interior of a stationary bobbin 22 supported at a point 23near its upper end. Another synthetic continuous filament thermoplasticyarn end 24 is withdrawn from a source 25 and wrapped in a series ofhelical turns 26 around the outside of the bobbin 22, the wrapping beingaccomplished in any suitable manner, not shown. Turns of the yarn end 24are progressively formed at the upper end and withdrawn at the lower endof the bobbin so that at point 27 each of the yarn ends 20 and 24 isplied together, being helically wound one with respect to the other, aswell known in the art.

The two-ply thermoplastic yarn 28 is brought into tangential contactwith the outside of a suitably metallic heater drum 30 shown more indetail in FIG. 3 and specifically forming the subject matter of my U.S.Pat. application Ser. No. 751,785 above referred to. The yarn enters theheater drum 30 at its inlet end 31 and progresses along the outside ofthe drum to the takeoff end 32.

At the inlet end 31 the yarn encounters a straight outside rightcylindrical portion 33 which is of short extent since its main functionis to preheat the yarn as it passes around the cylindrical portion. Thenin the form of FIGS. 1 and 3, the yarn encounters an abrupt descendingstep 34 which is placed approximately at the point where extensiveshrinkage occurs (nylon continuous filament undergoes 14 percentshrinkage in the thermoplastic range). A step dimension of 0.05 inch ona side has been found to be adequate. Then follows a smooth gradualdescending conical portion 35 to the takeoff end 32. While variousangles may be used on this descending conical portion, depending on theextent of backup of twist to be compensated for, the angle of theconical portion should preferably be in the range from about 5 to 25,and more desirably about 15 with respect to the axis of the drum.

Around the conical portion 35 of the drum there will suitably be fromthree to five or six loops of yarn 38, each of which passes around theoutside of a guidepost 37 which is positioned adjoining and off to oneside of the drum. The guidepost 37 may be stationary or it optionallymay rotate like a spool if desired, as shown in my copending applicationabove referred to.

The post 37 has guide grooves at the ends to retain the yarn.

A rim 40 at the inlet end prevents the yarn from running off the drum atthat end, and rim 41 at the takeoff end prevents the possibility thatthe yarn will run off the drum at that end, and rim 41 at the takeoffend prevents the possibility that the yarn will run off the drum at thatend.

In many installations the drum heater will provide all the heat that isnecessary, but in FIG. 1 I show an optional supplemental longitudinal orstrip heater 42 having a heating chamber 43 through which the plied yarn28 passes.

From the last heater, the plied yarn is guided over canted rolls 44 and45 so that it cools while twisted to begin the cooling operation. Thenthe yarn passes along a cooling groove 46 of a yarn cooler 47 best seenin FIGS. 4, 5, and 6. The groove is wide enough to admit the yarn withspace on either side as best seen in FIG. 6.

Distributed along the length of the groove at the back is a plurality oftransverse nozzles 48 which discharge a cooling gas, suitably air, froma plenum chamber 50 connected to a source, suitably compressed air, by aconnection 51. Using nylon yarn of the character discussed above, with acooling groove having a depth of 0.010 inch and a width of aboutoneeighth inch, nozzles about 0.034 inch in diameter every half inchhave proved to be adequate with air pressure supplied from the plenumchamber in a range which may vary between 5 and 30 psi. The yarn passingalong the groove tends to float or become airborne as shown in FIG. 6,and to center itself with respect to the groove because of Bernoullisprinciple, thus being cooled without the danger of abrasion which mightoccur if the yarn were following the outside surface of a metalliccooling element at this time. It should be remembered that rapid coolingis a very critical operation because the yarn tends to shrink veryrapidly.

After cooling, the plied ends are separated into bulked yarn ends 52 and53 which pass through guides 54 and 55 to form packages 56 and 57.

Thus the synthetic thermoplastic continuous filament yarn ends 20 and 24are first plied together and helically wound around one another and thenheat set and rapidly cooled and deplied to form bulked andstretch-capable yarn ends 52 and 53. Yarn of this character is believedto be of special value to produce the panty portion of ladiesstocking-and-panty combinations.

As the heater drum operates in FIG. 1, the tension on the individualturn may vary and rather than breaking the loops, readjustment is likelyto take place by slipping of the loops along the conical portions orfailing to slip along the conical portions of the drum heater and bypulling of loops from the cylindrical portion of the drum over the step.This effect varies with the extent to which twist backs up onto theconical portion of the drum as a result of the twist introduced and ofthe deplying action which separates the bulked ends. An'

equilibrium condition is reached between the tendency of the twist toback up onto the cone and the tendency of the loops to slip down thecone, and thus the machine operates effectively at high speed withoutserious breakage.

The drum 30, as shown in FIG. 3, has a hollow interior 58 so that it cansurround a heater. A suitably hollow shaft 60 is journaled onantifriction bearings 61 mounted in a housing 62, and at the outer endprovided with a flange 63. The shaft has an opening 64 which permits airto circulate to cool the bearings. At the outer end of the shaft 60there is provided a conical portion 65 which seats in a central conicalopening 66 on the drum and is held in place by a screw 67 threaded intothe end of the shaft. Depending on the installation, the drum may idleunder the forward motion imparted by the takeup mechanism to the yarn bymeans not shown, or the shaft may be driven, suitably by a drive whichhas limited torque capability, such as a shaded pole electric motor sothat the drum speed will respond to variations in the tendency of theyarn to move forward.

. Within the hollow of the drum there is placed a heater 68; While theheater can operate on steam, hot air or other suitable means, anelectric heater is shown. A suitably ceramic insulator 70 has a hollowcentral opening 71 large enough to pass the shaft 60 with properclearance, has a shank portion 72 extending forward within the hollow ofthe drum and inside the electric heater 68, and has a flange portion 73which extends outward against the flange 63 of the housing and isanchored to the housing by screws 74 extending into a mounting 75. Theguidepost 37 is mounted in a screw 76 which extends into the mounting75.

While it is preferred to provide the step 34 at the large end of thesmooth descending conical portion of the drum as shown in my copendingapplication above referred to, alternatively a step may be provided inthe small end connecting the conical portion to a smooth cylindricaltakeoff portion.

The drum is made of a heat-conducting metal, preferably aluminum. It ispreferable also to use a coating on the outside of the drum to guardagainst staining the yarn, and this may be a cerrnet coating.

In operation of FIG. 1 two ends of synthetic continuous filamentthermoplastic yarn are plied together so that each is twisted withrespect to the other and then the plied ends are passed in one or moreloops around the cylindrical pre-heating portion of the heater drum,passing around the guidepost as part of each loop. At the place wherethe most pronounced shrinkage takes place, the plied yarn falls over astep. Several loops of yarn are wrapped around a smooth descendingconical portion, each of these loops passing around the guidepost. Thenthe yarn passes through the cooling device of the invention, beingcarried along as it is airborne under the streams of cooling gas.Finally, the yarn is separated or deplied and the individual bulked yarnends having stretch characteristics are formed into packages.

On the heater drum an adjustment takes place brought about by backing upof twist from the point of separation of the bulked yarn ends to theheater drum, combined with the shrinkage effect, the adjustment beingpredominently on the conical portion toward the takeoff end of the drum.

The preferred embodiment of the invention appears diagrammatically inFIG. 2, in which false twist imparts bulk to thermoplastic yarn bytwisting the fibers to a predetermined number of twins per inch whilethe fibers are in softened condition due to the heat.

Yarn 20 from a source 21 passes through the hollow interior 76 of afalse twist spindle 77 mounted on suitable bearings (not shown) anddriven by a drive belt 78 travelling crosswise. The false twist spindlehas a twisting head 80 provided with a pin 81 around which the yarn iswrapped. The yarn then passes to a takeup bobbin 82 on which the yarn isdistributed by a traversing guide 83.

It will be evident that the pin 81 in the false twist head 80 provides abrake to the twist and that the false twist is applied upstream withrespect to this head. Thus in a particular embodiment the number ofturns of false twist applied while one inch of yarn is advancing may be70 turns in a 70 denier yarn, and 90 turns in a 40 denier yarn, by wayof example.

In the embodiment in FIG. 2 the false twist backs up to the yarn as itpasses over the drum heater 30, which is suitably supplemented by astrip heater 42. The heater will raise the yarn into the thermoplasticrange as described. Then the yarn will pass along the groove 46 of thecooling device 47, across the path of the jets of cooling gas 48. Thiscooling is' applied to the still false twisted heated yarn and sets thetwist, creating the memory condition which, once the yarn is downstreamfrom the twist head, makes the yarn bulkier even though the twist islost. It is important that the temperature be low enough after the yarnpasses through the twist head so that little or no permanent twist willbe removed. As the spindle speed increases, the number of wraps aroundthe drum heater can be increased to allow enough time to heat properlyto temperature. The rapid cooling necessary is imparted by the streamsof gas in the cooling groove.

In some cases it is desirable to impart a forward or lifting componentto the yarn as it is passing through the cooling groove. This isaccomplished as shown in FIG. 7 by directing the orifice 48 diagonallyforwardly so that they will impart a transverse component but also aforward or lifting component to the yarn as it progresses in thedirection of the arrow 84. The form of FIG. 7 is preferred for verticaluse of the cooling device.

In FIG. 8 I show a single step heater drum which may be used instead ofthe multistep drums of US. Pat. No. 3,420,983, above referred to, FIGS.1, 3 and 4. The rotating drum 30 has a right cylindrical portion 33 atthe inlet end 31, then an abrupt downward step 34, and then at theoutlet end 32, it has a right cylindrical portion 84 which is divided bygroove walls 85 into series yarn paths all of the same approximatediameter. The yarn passes around the separation pin 37 on each turn,passing from the inlet, over the step 34 and then, once it is heated toplastic temperature, through the grooves between the walls 85, in whichfalse twist backs up before the yarn is cooled by the cooling means ofthe inventian.

In view of my invention and disclosure, variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the process and machine shown, and I thereforeclaim all such insofar as they fall within the reasonable spirit andscope of my claims.

Having thus described my invention that I claim as new and desire tosecure by Letters Patent is:

1. ln textile machinery, means for progressing synthetic thermoplasticcontinuous filament yarn forward, means for false twisting the yarn asit is progressed, a rotatably mounted heater drum having an inlet endreceiving the yarn and a takeoff end directed toward the means for falsetwisting, the drum having an outside smooth cylindrical larger portionat the inlet end with which the yarn has contact, a smooth circularsmaller portion toward the takeoff end from which the yarn leavescontact with the outside of the drum, and a downward step at one end ofthe smooth circular smaller portion, heater means inside the drum, aguide post beside the drum around which the yarn is wrapped for part ofeach turn, walls forming a cooling groove along which the yarn passesbetween the heater drum and the means for false twisting, means forprogressing the yarn along the cooling groove and means for directing aplurality of streams of cooling gas into the groove against the yarn.

2. A machine of claim 1, in which the downward step is located at thelarge end of the circular smaller portion.

3. A machine of claim 1, in which the circular smaller portion is adescending conical portion.

4. A machine of claim 1, in which the circular smaller portion is aright cylinder.

5. In textile machinery, means for plying two ends of syntheticthermoplastic continuous filament yarn twisted with respect to oneanother, a rotatably mounted heater drum having an inlet end and atakeoff end, the drum having a smooth cylindrical larger portion at theinlet end of which the plied yam enters into contact with outside of thedrum, a smooth circular smaller portion toward the takeoff end fromwhich the plied yarn leaves contact with the outside of the drum, and adownward step at one end of the smooth circular smaller portion, heatermeans inside the drum, a guide post beside the dmm around which theplied yarn is wrapped for part of each turn, walls forming a coolinggroove along which the yarn passes after leaving the heater drum, meansfor progressing the yarn along the cooling groove, orifice meansdistributed along the cooling groove for directing a plurality ofstreams of cooling gas into the groove at right angles to the directionof yarn progression, and means beyond the cooling groove for separatingthe two yarn ends to produce bulked yarn.

6. A machine of claim 5, in which the circular smaller portion is adescending cone.

7. A machine of claim 6, in which the downward step is located at thelarge end of the conical portion.

8. A machine of claim 5, in which the circular smaller portion is aright cylinder.

9. A process of bulking synthetic thermoplastic continuous filamentyarn, which comprises twisting two ends of such yarn into plies,carrying the plied yarn around the outside of a smooth cglindricallarger portion of a rotatable eated drum an around a guide post in oneor more loops, carrying the plied yarn around the outside of a smoothcircular smaller portion of the heated drum and around the guide post inone or more loops, leading the yarn over an abrupt descending step atone end of the smooth conical portion, the temperature of heating of theyarn by the drum being within the thermoplastic range of the yarn,leading the plied yarn away from the drum adjacent to the small end ofthe conical portion, progressing the yarn along a groove, applyingagainst the side of the yarn as it progresses along the groove aplurality of cooling gas streams, and separating the yarn ends toproduce bulked yarn.

1. In textile machinery, means for progressing synthetic thermoplasticcontinuous filament yarn forward, means for false twisting the yarn asit is progressed, a rotatably mounted heater drum having an inlet endreceiving the yarn and a takeoff end directed toward the means for falsetwisting, the drum having an outside smooth cylindrical larger portionat the inlet end with which the yarn has contact, a smooth circularsmaller portion toward the takeoff end from which the yarn leavescontact with the outside of the drum, and a downward step at one end ofthe smooth circular smaller portion, heater means inside the drum, aguide post beside the drum around which the yarn is wrapped for part ofeach turn, walls forming a cooling groove along which the yarn passesbetween the heater drum and the means for false twisting, means forprogressing the yarn along the cooling groove and means for directing aplurality of streams of cooling gas into the groove against the yarn. 2.A machine of claim 1, in which the downward step is located at the largeend of the circular smaller portion.
 3. A machine of claim 1, in whichthe circular smaller portion is a descending conical portion.
 4. Amachine of claim 1, in which the circular smaller portion is a rightcylinder.
 5. In textile machinery, means for plying two ends ofsynthetic thermoplastic continuous filament yarn twisted with respect toone another, a rotatably mounted heater drum having an inlet end and atakeoff end, the drum having a smooth cylindrical larger portion at theinlet eNd of which the plied yarn enters into contact with outside ofthe drum, a smooth circular smaller portion toward the takeoff end fromwhich the plied yarn leaves contact with the outside of the drum, and adownward step at one end of the smooth circular smaller portion, heatermeans inside the drum, a guide post beside the drum around which theplied yarn is wrapped for part of each turn, walls forming a coolinggroove along which the yarn passes after leaving the heater drum, meansfor progressing the yarn along the cooling groove, orifice meansdistributed along the cooling groove for directing a plurality ofstreams of cooling gas into the groove at right angles to the directionof yarn progression, and means beyond the cooling groove for separatingthe two yarn ends to produce bulked yarn.
 6. A machine of claim 5, inwhich the circular smaller portion is a descending cone.
 7. A machine ofclaim 6, in which the downward step is located at the large end of theconical portion.
 8. A machine of claim 5, in which the circular smallerportion is a right cylinder.
 9. A process of bulking syntheticthermoplastic continuous filament yarn, which comprises twisting twoends of such yarn into plies, carrying the plied yarn around the outsideof a smooth cylindrical larger portion of a rotatable heated drum andaround a guide post in one or more loops, carrying the plied yarn aroundthe outside of a smooth circular smaller portion of the heated drum andaround the guide post in one or more loops, leading the yarn over anabrupt descending step at one end of the smooth conical portion, thetemperature of heating of the yarn by the drum being within thethermoplastic range of the yarn, leading the plied yarn away from thedrum adjacent to the small end of the conical portion, progressing theyarn along a groove, applying against the side of the yarn as itprogresses along the groove a plurality of cooling gas streams, andseparating the yarn ends to produce bulked yarn.